Gas turbine engines include compressor, combustor, and turbine sections. Some of the air compressed in the compressor may be redirected along secondary paths within the gas turbine engine to cool various portions of the combustor and turbine sections. This redirected compressed air is heated during compression and may be further heated by windage heating as the compressed air travels along the secondary paths and drags on rotating components. Some of this heated compressed air may enter an oil sump and may lead to oil degradation and to a power loss of the gas turbine engine.
U.S. Pat. No. 4,544,167 to C. Giroux discloses a turboexpander compressor for use in a gas processing system having a seal system that avoids communication of gas with the oil being pumped through the bearings. The device has a shaft carried in a housing on bearings with a compressor wheel on one side and an expander wheel on the other side. Labyrinth seals seal the wheels from the interior of the housing and the bearings. Mechanical seals are located between the bearings and the labyrinth seals for preventing leakage of oil. Gas is injected from the compressor discharge into a groove on the expander side of the shaft to provide a thermal barrier. The mechanical seals each have a rotating ring carried by the shaft and a nonrotating ring carried by the housing. The nonrotating ring is biased into the rotating ring by means of an O-ring. The O-ring is located in a groove in the bore and a recess formed in the nonrotating ring. The recess is offset to deform the ring and cause it to exert a force on the nonrotating ring against the rotating ring.
The present disclosure is directed toward overcoming one or more of the problems discovered by the inventors.